1. Field of the Invention
This invention relates to a simulator for automatic vehicle transmission controllers or control systems.
2. Description of the Related Art
The assignee proposes, in Japanese Laid-Open Patent Application Hei 8 (1996)-121583, a simulator having computer-aided design programs or packages for automatic transmission controllers or control systems which measures the running conditions of the vehicle at intervals, calculates verification indices relating to the shift shock based on the measured data, and sorts and outputs the calculation results by the manipulation of a device such as throttle opening and modes of shift, etc. Thus, the simulator permits simulation of the real-world controllers or control systems and aids automotive engineers in modifying the shift characteristics of the automatic transmission control.
A recent development among such a simulators is the development of one which can simulate the real-world transmission controllers or control systems in real time and aids the engineer in analyzing and verifying the control algorithm. However, even if the automatic transmission has accurately been modelled, since the model must include the non-linear behavior of hydraulic actuators (such as clutches) in the transmission, it is quite difficult to simulate the control in real time even when a high-performance computer is used. Here, the term “real time” is used to indicate simulation time with the property that a given period of actual time represents the same period of time in the system being modelled.
The non-linear behavior of the hydraulic actuator can be often described with the use of a λ-function and an integral factor in the simulation model. However, since this configuration usually requires computation at a relatively short cycle or intervals such as 1 μsec, the computation becomes highly frequent and hence, it will take much time to simulate the events even in a single shift.